What is Sound?

When we first learned about sound in school, we probably learned that sound travels in "sound waves" as if it is a thing that travels in wiggly lines through space. 

But this isn't correct. Sound isn't a substance that travels through space. In fact sound doesn't travel through empty space at all! (Yes, many movies get this wrong).

Sound is the outcome of atoms and molecules vibrating in a wave-like pattern. 

We can unpack this in detail by separating the atoms (OBJECTS) from their motion (ACTION) and the wave pattern they create (OUTCOME).

If we strike a piece of metal, the atoms in the metal start to vibrate. This vibration is an ACTION. Those vibrating metal atoms bump into the surrounding air molecules (OBJECTS), transferring the ACTION of vibration to them. These air molecules then bump into their neighbors, passing the vibration along in a chain reaction.

Crucially, the air molecules themselves do not travel from the metal to your ear. They simply jiggle back and forth, passing the energy of motion along like people in a stadium wave. This coordinated, traveling pattern of vibrations is the OUTCOME: a sound wave.

When this wave of vibrating molecules reaches your ear, it sets your eardrum atoms into the same vibrational ACTION. Your brain interprets this specific pattern of motion—its frequency and intensity—as pitch and volume (INFORMATION).

By anchoring the explanation in atoms (OBJECTS) and their vibrations (ACTIONS), we replace magical thinking with mechanism. Sound isn't a mysterious "thing" that floats through the air; it's a pattern of motion (OUTCOME) you can predict and understand. This is the power of starting with the atomic model—it turns abstract phenomena into thinkable stories of cause and effect.

Many student (and adult) ideas about sound and how it works are misconceptions based on incorrect models and language introduced in the elementary grades. Students have many misconceptions about sound because they never learn what sound is from an atomic perspective (see below).

But if we learn about atoms first and then learn that atoms are always moving and that when they bump into other atoms they make those atoms move, then sound suddenly makes sense. 

Core Misconceptions About Sound

Misconception (Student's Idea)
Ontological Error / Flawed Model
Why It's Intuitive
Scientific Reality
1. Sound is a substance that travels.
"Sound fills the room like a gas."
OBJECT (Substance) vs. ACTION (Wave)
Sound can be "caught" (ear), "blocked," and seems to move from place to place. We noun-ify it ("the sound").
Sound is a mechanical wave—a propagating ACTION of vibrating particles. It's a process of energy transfer, not a moving object.
2. Sounds "live" inside objects.
"The bell has sound in it."
Property-as-Entity
The object (bell) is the source; the sound only exists when it acts. We confuse the potential to make sound with the sound itself.
The object has a structure that can vibrate (ACTION). Sound only exists while that vibration is happening and sending waves.
3. Loudness/Pitch are inherent properties of the source object.
"A big drum is always loud."
"A 'high' sound means it's physically higher up."
Confusing Intensive Properties
Links property directly to object size/location, not to the action of vibration (amplitude/frequency).
Loudness: OUTCOME of vibration amplitude (ACTION strength).
Pitch: OUTCOME of vibration frequency (ACTION speed).
4. Sound travels through empty space (a vacuum).
Missing the Medium
We see light go through space; sound seems similar. If air is "nothing," why can't sound go through it?
Sound requires a material medium (OBJECTS like air/water/solid particles) to transfer the vibration ACTION. No particles = no sound.
5. The ear "sucks in" or "collects" sound.
"My ears reach out to grab the sound."
Reversed Agency
We actively listen; ears feel like active organs. The ear is seen as the actor, not the receiver.
The ear is a detector. Sound waves (ACTION) cause the eardrum to vibrate. The ear is acted upon.
6. Sound waves are like water waves (or "wiggly lines" in air).
Misapplied Visual Model
We draw sound as squiggly lines. Students imagine air "wiggling" in place like a rope, or that air particles travel with the sound.
Air particles vibrate back-and-forth in place (ACTION) like a stadium wave, transferring energy neighbor-to-neighbor. They do not travel across the room.
7. Sound travels instantly or only in one direction.
Misunderstanding Speed & Propagation
We hear things as they happen; there's no visible lag for nearby sounds. Sounds also seem to come "from" a source directionally.
Sound is fast but has a finite speed. It propagates outward in all directions (like an expanding sphere) from the vibrating source.
8. Matter is created or used up when sound is made.
"You use up air to make sound."
Matter-Energy Confusion
Making sound feels like an exertion that could consume something.
Sound transfers motion not matter. The air molecules are the same before, during and after - they just move temporarily.